OPUS: Is habitat fragmentation detrimental or beneficial? Promoting our understanding of a contentious ecological question via synthesis.

About This Grant

When land is cleared for human activities, any remaining habitat is often found in isolated patches surrounded by very distinct land cover. This process, commonly referred to as ‘habitat fragmentation’, is hypothesized to be a major threat to the integrity of ecosystems worldwide. Studies to date have documented a wide variety of biological and environmental changes in habitat fragments, which is why many have concluded that the ecological consequences of habitat fragmentation will be severe, detrimental, and long-lasting. Whether the effects of habitat fragmentation on biodiversity are indeed detrimental, however, has emerged as one of the most contentious contemporary debates in ecology. At the core of this debate is that while habitat loss and fragmentation often occur simultaneously, they are actually distinct processes with potentially unique impacts on biodiversity. This means that detrimental effects attributed to fragmentation could instead be due to habitat loss. To address this contentious topic, the research team will synthesize multiple data sets collected over the course of two decades on the biology of the Amazonian understory plant Heliconia acuminata. In addition to generating a novel understanding of the relative impacts of habitat loss and fragmentation on biodiversity, it will also motivate future population-focused research on how these impacts might differ between functional groups. In doing so the researchers will also be generating publicly available data sets and computer code for use by the research community and peer-reviewed educational materials on the effects of tropical deforestation for use in undergraduate STEM courses. To isolate the effects of habitat loss and fragmentation on population viability, the researchers will model H. acuminata population dynamics in simulated landscapes that vary in the total amount of habitat and the size and arrangement of habitat fragments. The researchers will determine if there is a relationship between spatiotemporal variation in environmental conditions and demographic vital rates; the nature of this relationship will inform the type of Integral Projection Model used to simulate population dynamics in patches connected by seed-dispersing birds. These spatially-explicit demographic models will be used to determine (1) if there is a threshold amount of habitat below which patch configuration fails to increase landscape-level viability, (2) if there is a threshold amount of habitat above which landscape-level viability is assured regardless of how habitat patches are configured, and (3) how habitat fragmentation mediates the role of habitat configuration in landscapes with the same amount of total habitat. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.